A deputy mayor of Paris was killed in his car, one evening when he was driving home a young social worker with whom he had just spent the evening. Is this a crime of passion or a political assassination? Revel and Rousseau wonder about the real motive of the killer. But soon, they understand that it is in reality the social worker who was targeted. The murder of the politician would only be a smokescreen intended to blur the tracks and to keep investigators away from a gifted 10-year-old boy, perhaps at the heart of this bloody affair ...